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A roof pentaprism used in Single-lens reflex cameras; the lower right face is the roof (dach). An Amici roof prism. A roof prism, also called a Dachkanten prism or Dach prism (from German: Dachkante, lit. "roof edge"), is a reflective prism containing a section where two faces meet at a 90° angle, resembling the roof of a building and thus the name.
Dielectric phase-correction prism coatings are applied in a vacuum chamber with maybe 30 different superimposed vapor coating layers deposits, making it a complex production process. In a roof prism without a phase-correcting coating, s-polarized and p-polarized light each acquire a different geometric phase as they pass through the upper prism.
A toric lens is a lens with different optical power and focal length in two orientations perpendicular to each other. One of the lens surfaces is shaped like a "cap" from a torus (see figure at right), and the other one is usually spherical. Such a lens behaves like a combination of a spherical lens and a cylindrical lens.
Sony (formerly Minolta) offered a 500 mm catadioptric lens for their Alpha range of cameras. The Sony lens had the distinction of being the only reflex lens manufactured by a major brand to feature auto-focus (aside from the identical Minolta-manufactured lens that preceded Sony's production).
The F was a modular system camera, with various assemblies such as viewfinders, focusing screens, and motor drives for 36-exposure and 250-exposure film cassettes.Third parties manufactured other film backs, such as two Speed Magny film backs—one using Polaroid 100 (later 600) type pack films, and another designed for 4x5 film accessories including Polaroid's own 4x5 instant film back.
A Fresnel lens (/ ˈ f r eɪ n ɛ l,-n əl / FRAY-nel, -nəl; / ˈ f r ɛ n ɛ l,-əl / FREN-el, -əl; or / f r eɪ ˈ n ɛ l / fray-NEL [1]) is a type of composite compact lens which reduces the amount of material required compared to a conventional lens by dividing the lens into a set of concentric annular sections.